diff --git a/data-prepper-api/src/main/java/org/opensearch/dataprepper/model/event/JacksonEvent.java b/data-prepper-api/src/main/java/org/opensearch/dataprepper/model/event/JacksonEvent.java
index 741216becc..5ead432c87 100644
--- a/data-prepper-api/src/main/java/org/opensearch/dataprepper/model/event/JacksonEvent.java
+++ b/data-prepper-api/src/main/java/org/opensearch/dataprepper/model/event/JacksonEvent.java
@@ -61,6 +61,8 @@ public class JacksonEvent implements Event {
 
     private static final Logger LOG = LoggerFactory.getLogger(JacksonEvent.class);
 
+    private static final int FILL_OUT_OF_BOUNDS_ELEMENTS_LIMIT = 0;
+
     private static final String SEPARATOR = "/";
 
     private static final ObjectMapper mapper = JsonMapper.builder()
@@ -195,8 +197,31 @@ private JsonNode getOrCreateNode(final JsonNode node, final String key) {
         JsonNode childNode = node.get(key);
         if (childNode == null) {
             childNode = mapper.createObjectNode();
-            ((ObjectNode) node).set(key, childNode);
+            if (node.isArray()) {
+                int index = Integer.parseInt(key);
+                ArrayNode arrayNode = (ArrayNode) node;
+
+                int distanceFromArrayEnd = index - arrayNode.size();
+                if (distanceFromArrayEnd >= FILL_OUT_OF_BOUNDS_ELEMENTS_LIMIT + 1) {
+                    throw new IndexOutOfBoundsException(
+                            String.format("Cannot expand array past the limit of size %s to reach index %s", arrayNode.size(), index));
+                }
+                while (arrayNode.size() <= index) {
+                    arrayNode.addNull();
+                }
+
+                JsonNode existing = arrayNode.get(index);
+                if (existing == null || !existing.isObject()) {
+                    childNode = mapper.createObjectNode();
+                    arrayNode.set(index, childNode);
+                } else {
+                    childNode = existing;
+                }
+            } else {
+                ((ObjectNode) node).set(key, childNode);
+            }
         }
+
         return childNode;
     }
 
diff --git a/data-prepper-api/src/test/java/org/opensearch/dataprepper/model/event/JacksonEventTest.java b/data-prepper-api/src/test/java/org/opensearch/dataprepper/model/event/JacksonEventTest.java
index a1fd74b1e1..49d8385d77 100644
--- a/data-prepper-api/src/test/java/org/opensearch/dataprepper/model/event/JacksonEventTest.java
+++ b/data-prepper-api/src/test/java/org/opensearch/dataprepper/model/event/JacksonEventTest.java
@@ -18,6 +18,7 @@
 
 import java.math.BigDecimal;
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
@@ -147,6 +148,81 @@ void testPutAndGet_withStrings_eventKey(final String key) {
         assertThat(result, is(equalTo(value)));
     }
 
+    @Test
+    void testPutAndGet_withArrays_eventKey() {
+
+        final String key = "list-key/0/foo";
+        final String newValue = UUID.randomUUID().toString();
+
+        final List<Map<String, Object>> listValue = new ArrayList<>();
+        final Map<String, Object> mapValue = Map.of("foo", "bar", "foo-2", "bar-2");
+        listValue.add(mapValue);
+
+        final String listKey = "list-key";
+        final EventKey eventKey = new JacksonEventKey(listKey);
+        event.put(eventKey, listValue);
+
+        final Map<String, Object> expectedMap = new HashMap<>();
+        expectedMap.put(listKey, listValue);
+
+        assertThat(event.toMap(), equalTo(expectedMap));
+
+        final EventKey eventNestedKey = new JacksonEventKey(key);
+        event.put(eventNestedKey, newValue);
+
+        final List<Map<String, Object>> newlistValue = new ArrayList<>();
+        final Map<String, Object> newMapValue = Map.of("foo", newValue, "foo-2", "bar-2");
+        newlistValue.add(newMapValue);
+
+        expectedMap.put(listKey, newlistValue);
+
+        assertThat(event.toMap(), equalTo(expectedMap));
+
+
+        final List<Map<String, Object>> result = event.get(listKey, List.class);
+        assertThat(result, equalTo(newlistValue));
+
+        final String resultValue = event.get(key, String.class);
+        assertThat(resultValue, equalTo(newValue));
+    }
+
+    @Test
+    void testPutAndGet_withArrays_out_of_bounds_on_end_of_list_creates_new_element() {
+
+        final String key = "list-key/1/foo";
+        final String fooValue = UUID.randomUUID().toString();
+
+        final List<Map<String, Object>> listValue = new ArrayList<>();
+        final Map<String, Object> mapValue = Map.of("foo", "bar", "foo-2", "bar-2");
+        listValue.add(mapValue);
+
+        final String listKey = "list-key";
+        final EventKey eventKey = new JacksonEventKey(listKey);
+        event.put(eventKey, listValue);
+
+        event.put(key, fooValue);
+
+        final String resultValue = event.get(key, String.class);
+        assertThat(resultValue, equalTo(fooValue));
+    }
+
+    @Test
+    void testPutAndGet_withArrays_out_of_bounds_throws_IndexOutOfBoundsException() {
+
+        final String key = "list-key/3/foo";
+        final String fooValue = UUID.randomUUID().toString();
+
+        final List<Map<String, Object>> listValue = new ArrayList<>();
+        final Map<String, Object> mapValue = Map.of("foo", "bar", "foo-2", "bar-2");
+        listValue.add(mapValue);
+
+        final String listKey = "list-key";
+        final EventKey eventKey = new JacksonEventKey(listKey);
+        event.put(eventKey, listValue);
+
+        assertThrows(IndexOutOfBoundsException.class, () -> event.put(key, fooValue));
+    }
+
     @Test
     public void testPutKeyCannotBeEmptyString() {
         Throwable exception = assertThrows(IllegalArgumentException.class, () -> event.put("", "value"));
@@ -1117,5 +1193,4 @@ private static Stream<Arguments> getBigDecimalPutTestData() {
                 Arguments.of("1.000")
         );
     }
-
 }
diff --git a/data-prepper-plugins/mutate-event-processors/src/test/java/org/opensearch/dataprepper/plugins/processor/mutateevent/ConvertEntryTypeProcessorTests.java b/data-prepper-plugins/mutate-event-processors/src/test/java/org/opensearch/dataprepper/plugins/processor/mutateevent/ConvertEntryTypeProcessorTests.java
index bb5cf32983..34d396e876 100644
--- a/data-prepper-plugins/mutate-event-processors/src/test/java/org/opensearch/dataprepper/plugins/processor/mutateevent/ConvertEntryTypeProcessorTests.java
+++ b/data-prepper-plugins/mutate-event-processors/src/test/java/org/opensearch/dataprepper/plugins/processor/mutateevent/ConvertEntryTypeProcessorTests.java
@@ -389,4 +389,40 @@ void testEmptyKeyConvertEntryTypeProcessor() {
         when(mockConfig.getKey()).thenReturn("");
         assertThrows(IllegalArgumentException.class, () -> new ConvertEntryTypeProcessor(pluginMetrics, mockConfig, expressionEvaluator));
     }
+
+    @Test
+    void convert_type_on_value_in_array_element_converts_correctly() {
+        final String eventKey = "list-key/0/foo";
+
+        when(mockConfig.getType()).thenReturn(TargetType.fromOptionValue("long"));
+        when(mockConfig.getKey()).thenReturn(eventKey);
+
+        typeConversionProcessor = new ConvertEntryTypeProcessor(pluginMetrics, mockConfig, expressionEvaluator);
+
+        final Map<String, Object> eventData = new HashMap<>();
+
+        final List<Map<String, Object>> listElement = new ArrayList<>();
+        listElement.add(Map.of("foo", 10.0));
+
+        eventData.put("list-key", listElement);
+
+        final Event event = JacksonEvent.builder()
+                .withData(eventData)
+                .withEventType("event")
+                .build();
+
+        final List<Record<Event>> processedRecords = (List<Record<Event>>) typeConversionProcessor.doExecute(Collections.singletonList(new Record<>(event)));
+        assertThat(processedRecords.size(), equalTo(1));
+
+        final Event resultEvent = processedRecords.get(0).getData();
+
+        final Map<String, Object> resultEventData = resultEvent.toMap();
+
+        final Map<String, Object> expectedEventData = new HashMap<>();
+        final List<Map<String, Object>> expectedListElement = new ArrayList<>();
+        expectedListElement.add(Map.of("foo", 10L));
+        expectedEventData.put("list-key", expectedListElement);
+
+        assertThat(resultEventData, equalTo(expectedEventData));
+    }
 }